Systems and methods for the management of waste associated with processing guayule shrubs to extract rubber

ABSTRACT

Systems and methods for managing the waste associated with the extraction of rubber from guayule shrubs are provided. Also provided is a portable local sub-station for reducing the transportation costs associated with the processing of guayule shrubs for the extraction of rubber. Use of the disclosed systems, methods and/or local sub-station can reduce transportation costs, reduce processing costs and reduce the downstream processing complexity associated with the extraction of rubber from guayule shrubs.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No. 16/662,649 which was filed on Oct. 24, 2019 and has been assigned U.S. Pat. No. 11,267,019 and is a continuation of U.S. application Ser. No. 14/409,117 which was filed on Dec. 18, 2014 and has been assigned U.S. Pat. No. 10,471,473 and which claims priority to and benefit of PCT Application No. PCT/US2013/046328 filed Jun. 18, 2013 which claims priority to and any other benefit of U.S. Provisional Patent Application Ser. No. 61/660,983, filed Jun. 18, 2012, and entitled “Systems and Methods for the Management of Waste Associated with Processing Guayule Shrubs to Extract Rubber,” the entire disclosure of each of which is hereby incorporated by reference.

BACKGROUND

The guayule shrub is a well-known source of natural rubber (also called polyisoprene). This shrub stores rubber within the individual cells of the plant (e.g., stems, roots or leaves). While precise amounts may vary depending upon age of the shrub, growing conditions and species, the guayule shrub generally contains 1-10 weight percent rubber. Processes for removing the rubber from the guayule shrub generally entail extraction of rubber and resin from the shrub and the creation of a large amount of waste material which is primarily non-soluble woody material (commonly referred to as bagasse).

SUMMARY

Provided herein are systems and methods for managing the waste associated with the extraction of rubber from guayule shrubs. Also provided herein is a portable local sub-station for reducing the transportation costs associated with the processing of guayule shrubs for the extraction of rubber. Use of the disclosed systems, methods and/or local sub-station can reduce transportation costs, reduce processing costs and reduce the downstream processing complexity associated with the extraction of rubber from guayule shrubs.

In a first embodiment, a method for managing waste associated with the processing of guayule shrubs for the extraction of rubber is provided. The method comprises utilizing harvested guayule shrubs including leaves, bark, woody material, and optionally roots from a harvest site; utilizing a local sub-station to remove at least one of the leaves and dirt from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 10% lower than the weight of the harvested guayule shrubs; and transporting the semi-processed guayule material to a remote rubber extraction plant capable of producing rubber, resin and waste bagasse from the semi-processed guayule material where the waste bagasse comprises at least 60% by weight of the semi-processed guayule material.

In a second embodiment, a portable local sub-station for reducing the transportation costs associated with the processing of guayule shrubs for the extraction of rubber is provided. The portable local sub-station comprises at least one of a chopper, a debarker, a briquetting machine, an air separator, a leaf remover and a compression machine suitable for initial processing of a quantity of harvested guayule shrub thereby reducing the weight of the harvested guayule shrub by at least 5%. The local sub-station is capable of being transported to multiple locations.

Also provided herein are systems relating to the processing of guayule shrubs for the extraction of rubber. In a first system embodiment, a system for managing waste associated with the processing of guayule shrubs for the extraction of rubber is provided. The system comprises a sub-system for receiving harvested guayule shrubs including leaves, bark, woody material and optionally roots from a harvest site; a pre-processing sub-system comprising a local sub-station for removing at least one of the leaves and root dirt from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 5% lower than the weight of the harvested guayule shrubs.

In a second system embodiment, a system for pre-processing guayule shrubs prior to the extraction of rubber from the shrubs is provided. The system comprises a pre-processing sub-system comprising a local sub-station for receiving harvested guayule shrubs from a harvest site and for removing at least one of the leaves and root dirt from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 5% lower than the weight of the harvested guayule shrubs, wherein the local processing sub-system is located within 25 miles of the harvest site.

DETAILED DESCRIPTION

Provided herein are systems and methods for managing the waste associated with the extraction of rubber from guayule shrubs. Also provided herein is a portable local sub-station for reducing the transportation costs associated with the processing of guayule shrubs for the extraction of rubber. Use of the disclosed systems, methods and/or local sub-station can reduce transportation costs, reduce processing costs and reduce the downstream processing complexity associated with the extraction of rubber from guayule shrubs.

Definitions

The terminology as set forth herein is for description of the embodiments only and should not be construed as limiting the invention as a whole.

As used herein, the term non-Hevea plant is intended to encompass plants that contain natural rubber within the individual cells of the plant.

As used herein the term “bagasse” is used to refer to that portion of the ground or chopped plant matter from a non-Hevea plant that is insoluble and hence is suspended rather than dissolved by organic solvents. As used herein, bagasse should be understood to include dirt and ash, unless otherwise specified.

As used herein the term “plant matter” means material obtained from a non-Hevea plant. Unless otherwise specified, the plant matter may include roots, stems, bark, woody material, pith, leaves and dirt.

As used herein the term “woody material” means the vascular tissue and meristematic material obtained from a non-Hevea plant. Unless otherwise specified, woody material does not include bark.

As used herein the term “bark” refers to the tough outer covering present on the stems and roots of certain (particularly woody or shrub-like) non-Hevea plants and should be understood to include all tissues outside the vascular cambium. Not all non-Hevea plants will contain bark.

As used herein the term “resin” means the naturally occurring non-rubber chemical entities present in non-Hevea plant matter, including but not limited to resins (such as terpenes), fatty acids, proteins, and inorganic materials.

As used herein the term “dirt” (such as used in the connection with the solid purified rubber produced by the processes disclosed herein) means non-plant material that may be associated with non-Hevea plants, particularly upon harvesting, such as soil, sand, clay and small stones. Dirt content in solid purified rubber can be determined by completely re-dissolving the solid rubber and pouring the solution through a 45 micron sieve. The sieve is then rinsed with additional solvent and dried. The weight of the material retained on the sieve represents the “dirt” content of the solid purified rubber.

In a first embodiment, a method for managing waste associated with the processing of guayule shrubs for the extraction of rubber is provided. The method comprises utilizing harvested guayule shrubs including leaves, bark, woody material, and optionally roots from a harvest site; utilizing a local sub-station to remove at least one of the leaves and dirt from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 10% lower than the weight of the harvested guayule shrubs; and transporting the semi-processed guayule material to a remote rubber extraction plant capable of producing rubber, resin and waste bagasse from the semi-processed guayule material where the waste bagasse comprises at least 60% by weight of the semi-processed guayule material. (It should be understood that the terms process and method, as used with respect to the first embodiment, are used interchangeably herein.)

In a first sub-embodiment of the first embodiment, a method for managing waste associated with the processing of guayule shrubs for the extraction of rubber is provided. The method comprises utilizing harvested guayule shrubs including leaves, roots, bark and woody material from a harvest site; utilizing a local sub-station to remove at least one of the leaves and root dirt from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 5% lower than the weight of the harvested guayule shrubs; and transporting the semi-processed guayule material to a remote rubber extraction plant capable of producing rubber, resin and waste bagasse from the semi-processed guayule material where the waste bagasse comprises at least 60% by weight of the semi-processed guayule material (on a dry weight basis).

In a second sub-embodiment of the first embodiment, a method for managing waste associated with the processing of guayule shrubs for the extraction of rubber is provided. The method comprises utilizing harvested guayule shrubs including leaves, bark and woody material from a harvest site; utilizing a local sub-station to remove at least one of the leaves and root dirt from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 5% lower than the weight of the harvested guayule shrubs; and transporting the semi-processed guayule material to a remote rubber extraction plant capable of producing rubber, resin and waste bagasse from the semi-processed guayule material where the waste bagasse comprises at least 60% by weight of the semi-processed guayule material (on a dry weight basis).

In a third sub-embodiment of the first embodiment, a method for managing waste associated with the processing of guayule shrubs for the extraction of rubber is provided. The method comprises utilizing harvested guayule shrubs including leaves, bark and woody material from a harvest site; utilizing a local sub-station to perform at least one of leaf removal, root dirt removal and woody material and bark separation from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 20% lower than the weight of the harvested guayule shrubs; and transporting the semi-processed guayule material to a remote rubber extraction plant capable of producing rubber, resin and waste bagasse from the semi-processed guayule material where the waste bagasse comprises at least 60% by weight of the semi-processed guayule material (on a dry weight basis).

In a second embodiment, a portable local sub-station for reducing the transportation costs associated with the processing of guayule shrubs for the extraction of rubber is provided. The portable local sub-station comprises at least one of a chopper, a debarker, a briquetting machine, an air separator, a leaf remover and a compression machine suitable for initial processing of a quantity of harvested guayule shrub thereby reducing the weight of the harvested guayule shrub by at least 5%. The local sub-station is capable of being transported to multiple locations.

Also provided herein are systems relating to the processing of guayule shrubs for the extraction of rubber. In a first system embodiment, a system for managing waste associated with the processing of guayule shrubs for the extraction of rubber is provided. The system comprises a sub-system for receiving harvested guayule shrubs including leaves, bark, woody material and optionally roots from a harvest site; a pre-processing sub-system comprising a local sub-station for removing at least one of the leaves and root dirt from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 5% lower than the weight of the harvested guayule shrubs; and a transportation sub-system for transporting the semi-processed guayule material to a remote rubber extraction plant capable of producing rubber, resin and waste bagasse where the waste bagasse comprises at least 60% by weight of the semi-processed guayule material (on a dry weight basis).

In a second system embodiment, a system for pre-processing guayule shrubs prior to the extraction of rubber from the shrubs is provided. The system comprises a pre-processing sub-system comprising a local sub-station for receiving harvested guayule shrubs from a harvest site and for removing at least one of the leaves and root dirt from the harvested guayule shrubs thereby producing a semi-processed guayule material with a weight that is at least 5% lower than the weight of the harvested guayule shrubs, wherein the local processing sub-system is located within 25 miles of the harvest site.

In a third system embodiment, a system for processing guayule shrubs to extract rubber from the shrubs that comprises a remote rubber extraction plant for receiving pre-processed guayule shrub material from a pre-processing site and for further processing the pre-processed guayule shrub material to produce rubber, resin and waste bagasse is provided. The pre-processed guayule shrub material that is received at the remote rubber extraction plant has been pre-processed to remove at least one of the leaves and root dirt thereby eliminating or reducing the need for such removal at the remote rubber extraction plant. In such embodiments, the remote rubber extraction plant is located more than 10 miles from the pre-processing site.

As previously discussed, in a first sub-embodiment of the first embodiment of the methods disclosed herein, the harvested guayule shrubs include leaves, roots, bark and woody material and the local sub-station of the first embodiment is used to remove at least one of the leaves and root dirt from the harvested guayule shrubs. In a second sub-embodiment of the first embodiment of the methods disclosed herein, the harvested guayule shrubs include leaves, bark and woody material and the local sub-station is used to remove at least one of the leaves and root dirt from the harvested guayule shrubs. In a third sub-embodiment of the first embodiment of the methods disclosed herein, the harvested guayule shrubs include leaves, bark and woody material and the local sub-station is used to perform at least one of leaf removal, root dirt removal and bark and woody material separation. (The harvested guayule shrubs that are utilized in the second embodiment and in the first, second and third embodiments of the systems disclosed herein can have any of the foregoing compositions.) Generally, leaf removal may be desirable because the leaves of the guayule shrub contain a relatively lower percentage of rubber as compared to the woody material. Similarly, it may also be desirable to remove the root dirt from the harvested guayule shrubs to prevent the dirt from entering the ultimate rubber extraction process since fine particles of dirt can contaminate the guayule rubber and lead to a lower grade, less desirable rubber product. In certain embodiments according to the first embodiment, separation of the bark and woody material from the harvested guayule shrubs may be desirable to form two streams of material from which rubber may be extracted. In certain embodiments, the bark stream and the woody material stream may be subjected to different subsequent treatments such as different types of compression into briquettes and even different rubber extraction procedures at a remote rubber extraction plant. In certain embodiments according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and of the systems disclosed herein and the second embodiment disclosed herein, the portable sub-station is used to remove the leaves and the root dirt from the harvested guayule shrubs. Generally, the incorporation of pre-processing processes such as one or more of leaf removal, root dirt removal, chopping, compression and bark and woody material separation at a location separate from the location where rubber extraction occurs can simplify the rubber extraction process in that relatively fewer steps (and, hence, relatively fewer pieces of equipment) are required during the rubber extraction process.

In certain embodiments according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and of the systems disclosed herein and the second embodiment disclosed herein, it may be desirable to have twigs and pieces of dead plant matter removed at the sub-station since these components have either lower overall rubber contents and/or contain degraded rubber (i.e., lower molecular weight).

In preferred embodiments according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and systems disclosed herein and the second embodiment disclosed herein, the local sub-station is located relatively near to the harvest site where the guayule shrubs are grown and harvested so as to facilitate easy delivery of the harvested guayule shrubs to the local sub-station. In certain embodiments, the sub-station is located within 25 miles, within 5 miles, within 1 mile, within ½ mile or even within ¼ mile of the harvest site. Conversely, the remote rubber extraction plant is located relatively remotely from the harvest site such that transportation of the entire guayule shrub without pre-processing at the local sub-station can lead to high transportation costs. In certain embodiments, the remote rubber extraction plant is located more than 10 miles, more than 25 miles or even more than 100 miles from the harvest site and/or from the site where the sub-station is located. It is specifically contemplated that the remote rubber extraction plant may take various forms and employ various processes for extracting the rubber from the guayule shrub, including, but not limited to aqueous extraction and organic solvent extraction. Exemplary methods for organic solvent extraction of rubber from guayule shrubs are disclosed in U.S. Patent Applications Ser. Nos. 61/607,448, 61/607,460 and 61/607,469, the entire disclosure of each being herein incorporated by reference.

In certain embodiments according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and according to the first, second and third embodiments of the systems disclosed herein the sub-station is portable. The degree of portability may vary. In preferred embodiments, the portable local sub-station may be located and utilized on a transportable platform or surface such as a trailer bed. In such embodiments, the re-location of the sub-station to a new sub-station location for initial processing of the harvested guayule shrub and/or the re-location of the sub-station to the remote rubber extraction plant will be relatively easy. In other embodiments, the sub-station may be portable in terms of being capable of being loaded onto a truck or moved via another transportation device for delivery to a suitable sub-station location or to the remote rubber extraction plant, off loaded from the transportation device and useable after placement on the ground, located at or near the harvest site or remote rubber extraction plant on a platform (with or without mounting fixtures) or temporarily installable in a building or other shelter (again, with or without mounting fixtures) at or near the harvest site or remote rubber extraction plant. Preferably, the portable sub-station is configured such that it is usable within no more than a few hours (i.e., 2-4 hours or less) of being moved to a new location. In certain embodiments according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and of the systems disclosed herein and according to the second embodiment disclosed herein, the sub-station is re-located from a first local location that is no more than 5 miles (preferably no more than 1 mile) from a first harvest site to a second local location that is not more than 5 miles (preferably no more than 1 mile) from a second harvest site. Such an embodiment allows for the movement of a local sub-station to more than one harvest site where the harvest sites may be different farm locations that are located various distances from each other (e.g., more than 10 miles apart, more than 20 miles apart or even more than 100 miles apart) and are also each relatively remote from the remote rubber extraction plant (e.g., each more than 10 miles from the remote rubber extraction plant). Such movement to accommodate various harvest sites can have the advantage of achieving more efficient use of equipment as a particular harvest site will likely only harvest guayule shrubs during a certain period or periods during the year.

The local sub-station may contain various types of equipment in order to remove at least one of the leaves, roots and bark from the harvested guayule shrub. Various methods for removing leaves from shrubs are known and the methods disclosed herein should not be considered to be particularly limited to any individual method. For example, in certain embodiments, leaf removal may be facilitated by the use of blown air, shaking or a combination of both. In certain embodiments, leaf removal can be facilitated by allowing the harvested guayule shrubs to dry in the field (e.g., for several days up to 2-3 weeks) whereby the leaves will tend to become dry and brittle and more easily removable. Various methods for removing dirt from the roots of shrubs exist and the methods disclosed herein should not be considered to be particularly limited to any individual method of root dirt removal. For example, in certain embodiments, root dirt removal may be achieved by shaking, vibrating, air blowing, air separator, and the use of water pressure. Various methods for separating or removing bark from the woody material of shrubs are known and the methods disclosed herein should not be considered to be particularly limited to any individual method of bark removal or separation. In certain embodiments, bark removal/separation can be facilitated by the use of a rice polisher, a drum debarker or a hydraulic debarker. A drum debarker uses a rotating drum to remove the bark. A hydraulic debarker uses high pressure water to remove the bark.

In certain embodiments according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and of the systems disclosed herein and the second embodiment disclosed herein, the local sub-station will also include a chopper that is capable of chopping the harvested guayule shrub into pieces having an average length of ¼″ to 4″. (Preferably, any chopping is conducted subsequent to the leaf removal and/or root dirt removal. However, in certain embodiments, depending upon the type of leaf removal and/or root dirt removal utilized, it can be feasible to chop the harvested guayule shrub into pieces prior to leaf removal and/or root dirt removal.) The chopped pieces may be more easily transported to the remote rubber extraction plant and can also decrease the amount of processing that is required at the remote rubber extraction plant during the rubber extraction process. Various methods exist for chopping woody materials such as guayule shrubs and the methods disclosed herein should not be considered to be particularly limited to any individual method. For example, one exemplary way of obtaining chopped plant matter is to feed raw plant material into a shredder, a granulator or a hammer mill. A granulator is a well-known machine designed for chopping or grinding material into various sizes. Most granulators contain multiple knives (often steel knives) and one or more screens (sometimes interchangeable) with various diameter holes to determine the size of the final product. Various size granulators exist and may be useful in chopping the plant matter such as those containing openings of ⅜″, ¼″ and ⅛″. A hammer mill can generally be described as a steel drum containing a vertical or horizontal rotating shaft or drum on which hammers are mounted; the hammers “pound” the material that is passed through the mill. Various size hammer mills exist and may be useful in chopping the plant matter such as those containing openings of ⅜″, ¼″ and ⅛″.

In certain embodiments according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and of the systems disclosed herein and according to the second embodiment disclosed herein, the local sub-station will also include a compression machine that is capable of compressing the chopped plant matter into a more dense form such as a briquette or a pellet. In certain embodiments, the compressed material is a briquette or pellet that has a density that is 150-325% higher than the density of the non-compressed chopped plant matter. Producing such briquettes at a location local to the harvest site or sites can lead to reduced shipping and transportation costs as relatively more briquettes (and, hence more rubber) can be transported to the remote rubber extraction plant or stored (at the location of the local sub-station, at the remote rubber extraction plant or at another location) within the same volume of shipping or storage container. In yet other embodiments, the briquettes have a density that is 40-100% higher than the density of the non-compressed chopped plant matter. Briquettes with such densities can provide advantages in terms of being easier to produce and easier to grind and dissolve in organic solvent. In certain embodiments, the briquettes have a density of 3 to 8.5 pounds/gallon (0.4 to 1 kg/liter). This density is the true density of the briquettes (excluding the volume of pores) and not a bulk density. Various methods (e.g., optical, gas expansion and liquid imbibitions) for determining the true density of a porous solid exist and are known to those skilled in the art, but they all generally entail measuring the volume of pores existing within the porous solid so that this volume can be excluded from the volume that is used to calculate true density.

In those embodiments of the first, second and third sub-embodiment of the first embodiment of the processes disclosed herein and of the systems disclosed herein and of the second embodiment disclosed herein, where the local sub-station includes a compression machine or briquetting machine, the briquettes, pellets or other compressed form that is produced may contain a certain amount of water. In certain embodiments, the briquettes contain 2-20% by weight water (based upon the total weight of the briquette). In other embodiments the briquettes contain 5-15% by weight water. The water that is within the briquettes has as its primary source residual water from the plant matter. The amount of water present in the briquettes can be adjusted such as by drying the chopped plant matter prior to compacting it into briquettes. In certain embodiments, the chopped plant matter is dried to reduce its moisture content by at least 2 weight %, by at least 4 weight % or even by at least 6 weight % prior to compacting the plant matter into briquettes. Various methods of achieving drying of the chopped plant matter can be utilized, including, but not limited to, sun drying, forced air drying (with air that is dry and/or heated). In certain embodiments, the plant matter may be dried prior to chopping. Another potential source for the water that may be present in the briquettes is additives added to the plant matter after harvest. As discussed in more detail later, these additives can include antioxidants and/or binders that may optionally be applied via aqueous solutions of the active ingredients.

In certain embodiments according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and of the systems disclosed herein and according to the second embodiment disclosed herein, the local sub-station includes a chopper. In certain such embodiments, the plant matter comprises chopped guayule shrub including bark and woody tissue from the shrub but with no more than 5 weight %, preferably no more than 4 weight % or no more than 3 weight % or even more preferably no more than 1 weight % of the plant matter comprising leaves from the guayule shrub. In certain of the foregoing embodiments, the guayule shrub used for the plant matter initially comprises both the above-ground portions and below-ground portions of the shrub (i.e., the stems (with bark, woody tissue and pith) and the roots). In other of the foregoing embodiments, the guayule shrub used for the plant matter initially comprises only the above-ground portions of the shrub (in other words, the roots are not included in the plant matter). The leaves of the guayule shrub may be removed using various methods such as field drying followed by shaking. Other methods for removing the leaves from the plant matter of the guayule shrub before incorporating that plant matter into briquettes may be utilized as the particular method for removing leaves is not considered to be a significant limitation of the processes and systems disclosed herein.

In certain embodiments, according to the first, second and third sub-embodiments of the first embodiment of the processes disclosed herein and of the systems disclosed herein and according to the second embodiment disclosed herein, the local sub-station prepares briquettes from plant matter containing a combination of bagasse, rubber and resin. In certain embodiments, the plant matter utilized in the briquettes includes bark, woody material, rubber and resin. In certain embodiments, woody material comprises at least 70 weight %, at least 80 weight %, at least 85 weight % or even at least 90 weight % of the briquette and the remaining amount of the briquette comprises bark and leaves. In order to achieve the foregoing make-up of plant matter within the briquette it may be necessary to remove or limit the amount of bark and leaves that is utilized within the plant matter and compacted into briquettes. In yet other embodiments, bark comprises at least 50 weight %, at least 60 weight %, at least 70 weight % or even at least 80 weight % of the briquettes and the remaining amount of the briquettes comprise woody material and leaves. In order to achieve the foregoing make-up of plant matter within the briquettes it will likely be necessary to remove or limit the amount of woody material and leaves that is utilized within the plant matte and compacted into briquettes. In certain embodiments, the briquettes comprise at least 80 weight % bark, less than 20 weight % woody material and less than 1 weight % leaves. In order to achieve the foregoing make-up of plant matter within the briquettes it will likely be necessary to remove or limit the amount of woody material and leaves that is utilized within the plant matter and compacted into briquettes. In yet other embodiments, the briquettes contain less than 5 weight % woody material, with the remaining amount of the briquettes comprising up to 95 weight % bark and preferably less than 2 weight % leaves, even more preferably less than 1 weight % leaves. Each portion of the plant matter (i.e., bark, woody material, roots and leaves) used within the briquettes will contain varying amounts of bagasse, rubber, resin and water.

As used herein the terms briquette and pellet are used interchangeably and should be construed broadly to encompass various forms or shapes, including, but not limited to, pellets, cubes, rectangular solids, spherical solids, egg-shaped solids, bricks and cakes. Various methods exist for compacting the plant matter into briquettes. One method of preparing briquettes from the plant matter is to utilize a commercial briquetting machine to prepare the briquettes. Various companies manufacture these machines and they are available in various sizes and specifications. Exemplary briquetting machines include those manufactured by K. R. Komarek, Inc. (Wood Dale, IL), including the roll-type briquetting machines model no. B 100R and BR200QC. Generally, a briquetting machine utilizes a roll-type system to compact material, with or without the addition of a binder to the material that is being compressed. Pressure can be applied by the machine in varying amounts depending upon the machine utilized, the properties of the chipped plant matter and the properties desired in the briquettes. In certain embodiments, briquettes of plant matter from guayule shrubs are made using a briquetting machine. In certain of the foregoing embodiments, a binder is applied to the chipped plant matter prior to its being compressed into briquettes. Other methods of preparing briquettes of chopped plant matter from non-Hevea plants may be utilized within the scope of the processes and systems disclosed herein. In this regard, the disclosure of U.S. Patent Application Ser. No. 61/607,475 entitled “Processes For Recovering Rubber From Non-Hevea Plants Using Briquettes” is herein incorporated by reference.

In certain embodiments, the briquettes made by the local sub-station are made from chopped plant matter that has been treated with one or more binders prior to compression into briquettes. Various types of binders may be utilized, including, but not limited to, organic-based binders (such as wood products, clay, starches and ash), chemical-based binders (such as -sulfonate, lime, and sodiumbentonite and liquids such as water. The amount of binder utilized with the chipped plant matter may vary depending upon the type of briquette being formed. In certain embodiments, the amount of binder utilized with the briquette is 0.1-5 weight % (based on the total weight of the briquette).

In certain embodiments, the briquettes made by the local sub-station are made from chopped plant matter that has been treated with one or more antioxidants prior to compression into briquettes. Suitable compounds for use as the one or more antioxidants in certain embodiments include, but are not limited to, 2,6-di-t-butyl-4-methylphenol (also known as 2,6-di-t-butyl-p-cresol); N-(1,3-dimethylbutyl)-N′-phenyl-1,4-benzenediamine; octadecyl-3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate (commercially available as Irganox® 1076); 4,6-bis (octylthiomethyl)-o-cresol (commercially available as Irganox® 1520), monohydric hindered phenols such as 6-t-butyl-2,4-xylenol, styrenated phenols, butylated octylphenols; bisphens, for example 4,4′-butylidenebis(6-t-butyl-m-cresol), polybutylated bisphenol A, hindered hydroquinones such as 2,4-di-t-amylhydroquinone; polyphenols, such as butylated p-cresol-dicyclopentadiene copolymer; phenolic sulfides such as 4,4′-thiobis(6-t-butyl-3-methyl-phenol), alkylated-arylated bisphenol phosphites such as tris(nonylphenyl)phosphite, triazinetriones such as alkylated hydroxycinnamate triester of tris(2-hydroxyethyl)-triazinetrione, tris(alkyhydroxybenzyl)-triazinetrione; pentaerythritol esters such as tetrakis(methylene-3,5-di-t-butyl-4-hydroxyhydrocinnamate)-methane; substituted diphenylamines such as octylated diphenylamines, p-(p-touenesulfonamido)-di-phenylamine, nonylated diphenylamine, diisobutylene-diphenylamine reaction products; dihydroquinolines such as 6-dodecyl-1,2-dihydro-2,2,4-trimethylquinoline; dihydroquinoline polymers such as 1,2-dihydro-2,2,4-trimethylquinoline polymer; mercaptobenz-imidazoles such as 2-mercaptobenzimidazole; metal dithiocarbamates such as nickel dibutyldithiocarbamate, nickel diisobutyldithiocarbamate, nickel dimethyldithiocarbamate; ketone/aldehyde-arylamine reaction products such as aniline-butyraldehyde condensation products, diarylamine-ketone-aldehyde reaction products; and substituted p-phenylenediamines such as di-b-naphthyl-p-phenylenephenylenediamine and N-phenyl-N′-cyclohexyl-p-phenylenediamine. The total amount of the antioxidant employed in those embodiments that utilize at least one antioxidant may be in the range of 0.2-2 weight % of the purified solid rubber ultimately produced by the process (based upon the weight of the purified solid rubber containing less than 0.8 weight % solvent).

In certain embodiments, the plant matter that is compressed into the briquettes by the local sub-station has not only been chopped but has also been subjected to a roller mill/cracker mill, flaker mill/flaker, hammer mill and/or other mechanical treatment capable of rupturing the cell walls of the cells that contain the natural rubber. A roller mill/cracker mill can generally be described as a device with two or more rolls each containing longitudinal grooves which assist in further size reduction of material fed through the mill. A flaker mill or flaker can generally be described as a device with two or more rolls each having a smooth surface, usually operated at different speeds, with a defined and adjustable clearance between rolls which primarily assist in providing further rupturing of plant cell walls. A hammer mill can generally be described as a steel drum containing a vertical or horizontal rotating shaft or drum on which hammers are mounted; the hammers “pound” the material that is passed through the mill. Such types of mechanical treatment tend to increase the amount of natural rubber that can ultimately be recovered from the plant matter. In certain embodiments, chopped plant matter from the guayule shrub is used for the briquettes, and the chipped plant matter is subjected to at least one of roll milling, flake milling and hammer milling prior to compression into a briquette. In those embodiments where at least one of roll milling, flake milling or hammer milling is used upon the chipped plant matter, the chopped plant matter is preferably treated with at least one antioxidant prior to being compressed into a briquette (the amount of the antioxidant being in accordance with the previous antioxidant discussion).

In certain embodiments, the briquettes are capable of being stored for at least 90 days after compacting while still having the rubber contained within the briquettes retain a molecular weight of at least 800,000, preferably at least 1,000,000. The briquettes may be stored at a location at or near the location of the sub-station, at or near the rubber extraction plant or at a separate location such as one capable of providing temperature or other environmental controls. In certain preferred embodiments, the briquettes are made of chopped plant matter from a guayule shrub and the briquettes are capable of being stored for at least 90 days after compacting while still having the rubber contained within the briquettes retain a molecular weight of at least 800,000, preferably at least 1,000,000. In other embodiments, the briquettes are capable of being stored for at least 7 months (210 days) after compacting while still having the rubber contained within the briquettes retain a molecular weight of at least 800,000, preferably at least 1,000,000. In certain preferred embodiments, the briquettes are made of chipped plant matter from a guayule shrub and the briquettes are capable of being stored for at least 7 months (210 days) after compacting while still having the rubber contained within the briquettes retain a molecular weight of at least 800,000, preferably at least 1,000,000.

While the sub-embodiments of the first, second and third embodiments of the first embodiment of the processes disclosed herein, the embodiments of the systems disclosed herein, and of the second embodiment disclosed herein have been discussed primarily in terms of one local sub-station and one remote rubber extraction plant, it should be considered to be within the spirit of the current disclosure to utilize more than one local sub-station and/or to utilize more than one remote rubber extraction plant. For example, depending upon the size and number of the harvest sites and the size of the remote rubber extraction, it may be advantageous to utilize more than one local sub-station (e.g., two local sub-stations, three local sub-stations or more).

To the extent that the term “includes” or “including” is used in the specification or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed (e.g., A or B) it is intended to mean “A or B or both.” When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into” are used in the specification or the claims, it is intended to additionally mean “on” or “onto.” Furthermore, to the extent the term “connect” is used in the specification or claims, it is intended to mean not only “directly connected to,” but also “indirectly connected to” such as connected through another component or components.

While the present application has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the application, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept. 

What is claimed is:
 1. A method for managing waste associated with the processing of guayule shrubs for the extraction of rubber, the method comprising: providing guayule shrubs comprising leaves, bark, woody material, and roots at a harvest site; utilizing a portable local sub-station comprising a chopper which reduces the guayule shrubs to a guayule plant matter with pieces having an average length of about ¼″ to about 4″, wherein only above-ground portions of the guayule shrubs are included in the guayule plant matter, thereby producing a semi-processed guayule material with a weight at least 5% lower than the weight of the guayule shrubs; and transporting the semi-processed guayule material to a remote rubber extraction plant capable of producing rubber, resin and waste bagasse from the semi-processed guayule material where the waste bagasse comprises at least 60% by weight of the semi-processed guayule material.
 2. The method of claim 1, wherein the portable local sub-station lacks any debarker, briquetting machine, air separator, leaf remover or compression machine.
 3. The method of claim 1, wherein the portable local sub-station further comprises at least one of a debarker, a briquetting machine, an air separator, a leaf remover or a compression machine.
 4. The method of claim 1, where the portable local sub-station is capable of being transported to multiple locations.
 5. The method of claim 1, wherein the portable local sub-station is mounted onto a trailer capable of being towed by a truck.
 6. The method of claim 1, wherein the remote rubber extraction plant is located at least 10 miles from the harvest site.
 7. The method of claim 1, wherein the remote rubber extraction plant is located at least 25 miles from the harvest site.
 8. The method of claim 1, wherein the chopper reduces the guayule shrubs to guayule plant matter with pieces having an average length of about 4″.
 9. The method of claim 1, wherein the chopper reduces the guayule shrubs to guayule plant matter with pieces having an average length of about ¼″.
 10. The method of claim 1, wherein the semi-processed guayule material is dried at the harvest site prior to transporting.
 11. The method of claim 1, wherein the remote rubber extraction plant performs organic solvent extraction.
 12. A method for managing waste associated with the processing of guayule shrubs for the extraction of rubber, the method comprising: providing guayule shrubs comprising leaves, bark, woody material, and roots at a harvest site; utilizing a portable local sub-station comprising a chopper which reduces the guayule shrubs to a guayule plant matter with pieces having an average length of about 4″, wherein only above-ground portions of the guayule shrubs are included in the guayule plant matter, thereby producing a semi-processed guayule material with a weight at least 5% lower than the weight of the guayule shrubs; and transporting the semi-processed guayule material to a remote rubber extraction plant capable of using organic solvent extraction to produce rubber, resin and waste bagasse from the semi-processed guayule material where the waste bagasse comprises at least 60% by weight of the semi-processed guayule material.
 13. The method of claim 12, wherein the portable local sub-station lacks any debarker, briquetting machine, air separator, leaf remover or compression machine.
 14. The method of claim 12, wherein the portable local sub-station further comprises at least one of a debarker, a briquetting machine, an air separator, a leaf remover or a compression machine.
 15. The method of claim 12, where the portable sub-station is capable of being transported to multiple locations.
 16. The method of claim 12, wherein the portable sub-station is mounted onto a trailer capable of being towed by a truck.
 17. The method of claim 12, wherein the remote rubber extraction plant is located at least 10 miles from the harvest site.
 18. The method of claim 12, wherein the remote rubber extraction plant is located at least 25 miles from the harvest site.
 19. The method of claim 12, wherein the semi-processed guayule material is dried at the harvest site prior to transporting.
 20. The method of claim 13, wherein the semi-processed guayule material is dried at the harvest site prior to transporting. 